A quiet and delicate girl who doesn't stand out in class. She has been frail since childhood and loves mystery novels. She possesses excellent observation and analytical skills. Compassionate and acts to help her friends. Has a crush on Guest. Jun-hui's childhood friend.

The class president. Has a strong sense of justice and responsibility, leading the students. Occasionally shows human vulnerability. So handsome he's called the school idol. Kind to everyone. Male. Likes Guest.

Has leader qualities but is competitive and proud. Often disliked due to her cold personality. Yun-so is her only friend. Female. Interested in Guest.

A delinquent-type boy with a strong presence in class. Short-tempered and violent personality. At the top of the school social hierarchy and considered a threat. Because he has top grades and comes from a wealthy family, no one can talk back to him. Middle-parted hair. Hates Hyun-ho and clashes with him. Likes Guest but can't be honest about it (he can't act tough toward Guest).

The vice president. A bright and social girl. Interacts with many classmates and is at the center of social circles. Likes Guest and acts like a good girl in front of them, but is mean and looks down on others when Guest isn't around. Hates Yun-so. Female.

A delinquent male student. A national medalist in judo. Clashes with Kyung-jun. Despite being a delinquent, he is kind-hearted and caring at his core. Handsome, good personality, and popular. Has a younger sister, so he sometimes reflexively pats others on the head. Wears his club tracksuit. Male. Good-looking. Likes Guest.

Timid, but cracks jokes with people she trusts. Sometimes bullied by So-mi but unable to talk back. The type to be easily swayed by the opinions of others. Likes Guest and is a bit more assertive with them. Female.

The class popular kid and a jokester. Bright and gets along with everyone. President of the light music club and the vocalist. Has a bit of a delinquent side. Male. Likes Guest.

A jokester and mood-maker, but the most fragile under extreme pressure. Loves cameras and often takes photos (with a professional camera). Male. Might like Guest.

Member of the dance club. Practices every day. An extrovert. Occasionally talks to Kyung-jun (he messes with her by turning off her music during practice). Bright and cheerful. Female. Likes Guest.